Optical and Electrical Properties of Pyrene–Imine Organic Interface Layer Based on p-Si

In the present study, 1,4-phenylenebis-1-(pyren-1-yl)methanimine derivative 3 (C40H24N2) was synthesized in high yield by condensation reaction of pyrene-1-carbaldehyde (1) with benzene-1,4-diamine (2). The structures of the obtained organic compound 3 were determined by nuclear magnetic resonance (NMR), infrared (IR), and high-resolution mass spectrometry (HRMS) spectroscopic techniques. An Al/C40H24N2/p-Si device was then fabricated using this pyrene–imine-based organic material 3 at the interface. The organic layer was coated on p-Si by the spin coating method, and ohmic and rectifier contacts were deposited by thermal evaporation. Besides optical measurements, such as ultraviolet (UV) absorbance and NMR, the electrical and photovoltaic properties were investigated by current–voltage (I–V) measurements in the dark and under different illumination conditions and capacitance–conductance–voltage (C–G–V) measurements at various frequencies. The electrical parameters of the device, such as ideality factor, barrier height, and series resistance, were calculated using three methods: thermionic emission theory (TE), Cheung method, and Norde functions. Using the TE method, the ideality factor value of the six devices (D1 to D6) obtained by coating the C40H24N2 organic layer between the metal and the semiconductor was 2.02 to 2.06, and the barrier height value increased by between 0.77 eV and 0.78 eV compared with the reference device. According to these results, the organic interface coated between the metal and semiconductor increased the barrier height and rectifying ratio of the device. In addition to its rectification feature, the Al/C40H24N2/p-Si/Al device showed photodiode characteristics. Although its solar cell parameters were low, these photodiode characteristics indicate that this device could be used in optoelectronic applications.